Mechanically-produced negative.



G. W. SGRITSMIER MEGHANICALLY PRODUCED NEGATIVE.

APPLICATION FILED NOV. 14, 1912.

1,090,240. Patented Mar. 17, 1914.

GEORGE W. SCRITSMIER, OF CHICAGO, ILLINOIS.

MECHANICALLY-PRODUCED NEGATIVE.

-Specification of Letters Patent.

Patented Mar. 17, 1914.

Application filed November 14, 1912. Serial No. 731,243.

, of Illinois, have invented certain new and useful Improvements inMechanically-Pro duced Negatives, of which the following isaspecification.

Myinvention relates to negatives or light stencils, and particularly tonegatives of the type described in my copending applications Serial No.715,360, filed August 16,

1912, and Serial No. 725,355 filed October 12, 1912. In theseapplications I described and claimed a method of reproducing on metalplates, which by subsequent treatment are converted into electrotypes orprinting plates, written or printed matter and particularly typewrittenmatter, by means of mechanicall' produced negatives or light stencils,an also the negative or stencil, and the process of making the same,employed by said method. The stencil in the then preferred formconsisted of a backing of celluloid, or other tough transparent ortranslucent material, and

a coating of waxy substance, for example, a mixture of, beeswax andparafiin, covered with printers ink preferably also containing some wax.The composite sheet of material thus produced, after being dried, wasput into a typewriter with the ribbon removed and the matter to bereproduced out or imprinted in the waxy stratum by direct contact of thetypewriter type therewith. The type out through the thin layer ofprinters ink and through the layer of waxy material, (these twomaterials being moreor less amalgamated) the waxy substance beingpressed back by the type. The negative or light stencil thus formed wasthen placed upon a sensitized metal plate and the plate exposed to lightwith the result that the typewritten matter was photographicallyreproduced on the plate. The plate was then developed and by subsequentfamiliar treatment converted into an electrotype or printing plate. Thismethod has been successfully practised but experience developed the needor advisability of devising some means for preventing the incisions inthe waxy stratum from being partially refilled if the best results wereto be obtained. A negative of this sort is subjected to veryconsiderable pressure during the printing operation. This pressure tendsto force the wax back into the incisions or indentations made by thetype, with the result that the outlines of the characters are not assharp and clean-cut as they should be. Hot weather or the heat resultingfrom the use of an arc lamp, for ex ample, in printing, tends toincrease this difliculty by softening the waxy stratum. Also with thenegatives constructed in accordance with my previous applications abovementioned there is a tendency to stick to the plate.

These defects are cured by my present invention which, broadly speaking,consists in filling the incisions in the plastic coating of the negativewith a gelatinous substance which is ut on as a thin water solution andafterwar dries and hardens. \Vhen a negative has been so treated it maybe subjected to any pressure and to any reasonable amount of heatwithout danger of obliterating the incised characters or destroying thesharpness and clearness of their outlines.

My invention is illustrated in the accompanying drawing, in whichsimilar characters of reference designate corresponding parts, and inwhich- Figure 1 is a plan view of a preferred embodiment of myinvention; and Fig. 2 is a sectional view taken on line 22 of Fig. 1,looking in the direction indicated by the arrows. For the purpose ofclearness the details are shown greatly exaggerated in the drawing.

Referring to the drawing, A designates the translucent and preferablyflexible backing on which a coat of wax B is superposed.

On the wax is asuperposed opaque coating C which is preferably a thinlayer of printers ink. After the application of the opaque coating andbefore the composite sheet is formed with light passages D, the sheet iswashed in a solution, the solvents of which will readily evaporate so asto leave a thin skin or deposit on the opaque waxy stratum, as shown atE. To form this thin skin or deposit the solution used is preferablyordinary collodion, the ether and alcohol constituents of which willevaporate, leaving a deposit of pyroxylin. The characters or lightpassages D are then cut through the strata B, C and E by means of atyqiewritor,

or in some other suitable manner. \Vhen a typewriter is used for cuttingthe light passages by the type face being forced into the waxy coatings,a shoulder such as shown at F is formed around the upper edge of saidpassages. After the desired light passages have been formed the negativeis coated with a dilute gelatinous substance Gr, for example, ordinarycommercial gelatin thinned out with water. This operation fills theincisions in the waxy stratum with gelatinous matter which, when dry,becomes quite hard so that it prevents the filling up of the incisions.This treatment also gives a glaze to the negative which prevents itssticking.

The washing of the sheet or film With pyroxylin is not absolutelyessential but it is preferable where the opaque stratum is waxy orgreasy in its character because in such case the gelatin does not takeas firm a hold on the negative as is desirable. It is likely to peel offwith use. By washing the sheet with collodion, or other similarsubstance, the adhesion of the subsequently applied gelatin is insured.

A negative made in accordance With my present invention is very durable,can be used many times, and will stand any required amountof pressureand heat.

I claim:

1. A negative comprising a translucent backing, a coating formed with alayer of waxy material covered with printers ink having light passagesthrough said waxy material and said ink, and a translucent filling insaid passages.

2. A negative comprising a translucent backing, an opaque stratum ofWaxy material glazed over with a thin skin of pyroxylin and providedwith light passages through said stratum and skin, and a translucentfilling in said passages.

3. A negative comprising a translucent celluloid backing provided with alayer of waxy material covered with printers ink and with a thin skin ofpyroxylin over the printers ink and having light passages impressedthrough said coatings, and a translucent, hard filling in said passages.

4. A negative comprising a translucent backing having an opaque waxycoating through which coating light passages have been impressed, saidwaxy coating being provided with a relatively hard translucent coatingextending into said light passages.

GEORGE W. SCRIT SMIER.

Witnesses L. A. FALKENBERG,

G, Y, SKINNER.

